const object = {
	deepCompare: function(x, y){
		var i, l, leftChain, rightChain;
		function compare2Objects(x, y) {
			var p;
			// remember that NaN === NaN returns false
			// and isNaN(undefined) returns true
			if (isNaN(x) && isNaN(y) && typeof x === 'number' && typeof y === 'number') {
				return true;
			}
			// Compare primitives and functions.
			// Check if both arguments link to the same object.
			// Especially useful on the step where we compare prototypes
			if (x === y) {
				return true;
			}
			
			// Works in case when functions are created in constructor.
			// Comparing dates is a common scenario. Another built-ins?
			// We can even handle functions passed across iframes
			if ((typeof x === 'function' && typeof y === 'function') ||
				(x instanceof Date && y instanceof Date) ||
				(x instanceof RegExp && y instanceof RegExp) ||
				(x instanceof String && y instanceof String) ||
				(x instanceof Number && y instanceof Number)) {
				return x.toString() === y.toString();
			}
			
			// At last checking prototypes as good as we can
			if (!(x instanceof Object && y instanceof Object)) {
				return false;
			}
			
			if (x.isPrototypeOf(y) || y.isPrototypeOf(x)) {
				return false;
			}
			
			if (x.constructor !== y.constructor) {
				return false;
			}
			
			if (x.prototype !== y.prototype) {
				return false;
			}
			
			// Check for infinitive linking loops
			if (leftChain.indexOf(x) > -1 || rightChain.indexOf(y) > -1) {
				return false;
			}
			
			// Quick checking of one object being a subset of another.
			// todo: cache the structure of arguments[0] for performance
			for (p in y) {
				if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
					return false;
				} else if (typeof y[p] !== typeof x[p]) {
					return false;
				}
			}
			
			for (p in x) {
				if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
					return false;
				} else if (typeof y[p] !== typeof x[p]) {
					return false;
				}
				
				switch (typeof(x[p])) {
					case 'object':
					case 'function':
						
						leftChain.push(x);
						rightChain.push(y);
						
						if (!compare2Objects(x[p], y[p])) {
							return false;
						}
						
						leftChain.pop();
						rightChain.pop();
						break;
					
					default:
						if (x[p] !== y[p]) {
							return false;
						}
						break;
				}
			}
			
			return true;
		}
		
		if (arguments.length < 1) {
			return true; //Die silently? Don't know how to handle such case, please help...
			// throw "Need two or more arguments to compare";
		}
		
		for (i = 1, l = arguments.length; i < l; i++) {
			
			leftChain = []; //Todo: this can be cached
			rightChain = [];
			
			if (!compare2Objects(arguments[0], arguments[i])) {
				return false;
			}
		}
		
		return true;
	}
};
export {
	object
}
